A printed circularly polarized half-moon monopole antenna

A novel printed circularly polarized monopole antenna is presented. It is fed by a microstrip line and consists of a triangular-shaped ground plane and a half-moon-shaped monopole element. Circular polarization is realized by asymmetry of the monopole location on the ground plane and by adjustment of the ground plane size. Measurement and simulation results are in a good agreement and measured data shows a fractional impedance bandwidth of 43% from 1.1 to 1.7 GHz and a 3 dB axial ratio of approximately 30% from 1.228 to 1.7 GHz.